Hydraulic fluid



Patented Feb. 6, 1934 1,945,543 v HYDRAULIC FLUID Arthur G. Weber andRichard B. Schneider, Wilmington, Del., assignors to E. I. du Pont doNemours & Company, poration of Delaware Wilmington, l )el., a cor- NoDrawing. Application March 29, 1932 Serial No. so1,ss1

14 Claims.

This invention relates to compositions of matter and more particularlyto fluids especially desirable for use in hydraulically operatedapparatus, such, for example, as hydraulic brake sys- 5 tems, hydraulicjacks, door checks, and shock absorbers, and the like. It has beenpreviously proposed to use solutions of ethyl alcohol and castor oil,and the like, for actuating the pressure-operated elements of hydraulicbrake systems and similarly operated apparatus. Up to the present time,however, the different solutions and mixtures proposed for thesepurposes have been characterized by numerous disadvantages, such, forexample, as asiflcation, giving rise to highly dangerous possibilitiesin connection with braking systems. Another undesirable characteristichas been the tendency toward solidification of such a mixture at thelower temperatures, making dangerous and at times impossible theutilization of saidpreviously proposed liquids in localities such as aresubject to low temperatures. Accompanying these disadvantageous featuresthere has existed an undesirably wide change in viscosity of previouslysuggested hydraulic fluids under varying temperatures. I

We have discovered, however, that a highly desirable fluid for use inhydraulically operated systems such as hydraulic brake systems,hydraulic aojacks, door checks, shock absorbers or the, like,

free from the disadvantages above outlined, is obtained by mixing withvarying proportions of an oil the product obtained as a by-product inthe catalytic hydrogenation of the oxides of carbon to methanol. Theseby-products comprise, for the most part, mixtures of alcohols of highmolecular weight together with small amounts of other unidentifiedorganic compounds containing oxygen.

40- Other oils may be used instead of castor oil altho we have found itto possess those characmixture of such higher molecular weight alcoholsis suitable for use, in admixture with castoroil or the like, forhydraulically operated systems,

m we have found that certain fractions of said complete lay-product arepreferable, especially that fraction boiling between the range of from133 C. to 250 C'.-

Compared with hydraulic fluids hitherto suggested the mixtures preparedaccording to our in- 6h vention possess highly improved characteristicsfor utilization in hydraulic apparatus generally. Thus, for example, theviscosity of the fluid of our invention is highly uniform throughout awide temperature range. Furthermore, our fluid has considerably lessexpansion than those previously used, does not precipitate under lowtemperatures, and in addition to the castor oil or the like the mixtureof higher molecular weight alcohols contained therein has of itself adesirable lubricating value. Moreover, our fluid is free from theobjectionable gasiflcation phenomena found in other fluids, and exertsno disadvantageous corrosive action upon the metallic parts with whichit, comes in contact.

Although the invention is in no way limited thereby and the proportionsof constituents may be varied over a wide range, below are given certainspecific fractions, of indicated boiling point range, of the by-productobtained in the catalytic hydrogenation of the oxides of carbon tomethanol, together with the specific proportions in which they, mixedwith castor oil, blown rape seed oil and liquid petrolatum, may beutilized for a desirable hydraulic fluid possessing the requisiteviscosity characteristics at the extremes of the temperature encounteredin hydraulically operated apparatus.

Although the invention will be understood as I not limited thereto beloware also indicated specific uses to which hydraulic fluids of ourinvention may be put.

Hydraulic brake fluid Parts by weight l y paoguct gbg lgz o olbllyE 9 Y08 alytic hydrogenaa- 6 P not fraction tion of oxides of I carbon I g 5g; 5 C. and above. as 15' v boo-1W0, v g? }l64-169 0. m5 50 50 147-151"0.

t z? 93, 7 lac-154 0. 95 5 Shock absorber fluid Blown rape seed 011 41.668.5 195 C.and above. 31.5 68.5 157-195 C.

Castor oil 94. 6 5. 5 195 0. and above.

Door check fluid 62 38 160 C. and above Hydraulic :iaclc fluid I Liquidj petrolatum 25 160 C. and above Various changes may be made in themethod described without departing from the invention or sacrificing anyof the advantages thereof.

We claim:

1. A fluid for use in fluid pressure apparatus comprising an oilcharacterized by low solidifying point, and stability at hightemperature, and a mixture of higher boiling oxygenated organic liquidproducts obtainable as a by-product in the catalytic hydrogenation ofoxides of carbon to methanol.

2. A fluid for use in fluid pressure apparatus comprising on oilcharacterized by low solidifying point, stability at high temperatures,and a mixture of higher boiling oxygenated organic liquid productsboiling above 133 C. obtainable as a by-product by the catalytichydrogenation of oxides of carbon to methanol.

3. A fluid for use in fluid pressure apparatus comprising an oilcharacterized by low solidifying point, stability at high temperatures,and a mixture of the higher boiling oxygenated organic liquid productsobtainable as a by-product in the catalytic hydrogenation of oxides ofcarbon to methanol, in the proportions of from 5-195 parts of saidproduct to 95-5 parts of said o1 4. A fluid for use in fluid pressureapparatus comprising an oil characterized by low solidifying point,stability at high temperatures, and a mixtureof the higher boilingoxygenated organic liquid products boiling above 133 C. obtainable as aby-product by the catalytic hydrogenation of oxides of carbon tomethanol, in the proportions of from 5-95 parts of said products to from95-5 parts of said oil.

5. A fluid for use in fluid pressure apparatus comprising an oilcharacterized by low solidifying point, stability at high temperatures,and a mixture of the higher boiling oxygenated organic liquid productsboiling from 133 C. to 250 C. obtainable as a by-product by thecatalytic hydrogenation of oxides of carbon to methanol, and consistingprincipally of a mixture of alcohols of high molecular weight in theproportion of 5-95 parts of said product to 95-5 parts'of said 011.!

6. A fluid for use in fluid pressure apparatus comprising castor oil anda mixture of higher boiling oxygenated organic liquid productsobtainable as a by-product in the catalytic hydrogenation of oxides ofcarbon to methanol.

7. A fluid for use in fluid pressure apparatus comprising castor oil anda mixture of higher boiling oxygenated organic liquid products boilingabove 133 C. obtainable as a by-product by the catalytic hydrogenationof oxides of carbon to methanol and consisting principally of a mixtureof alcohols of high molecular weight, in the proportions of from 5-95parts of said products to from 95-5 parts of castor oil.

8. A fluid for use in fluid pressure apparatus comprising castor oil anda mixture of the higher boiling oxygenated organic liquid productsboiling from 147 C. to 157 C. obtainable as a. byproduct by thecatalytic hydrogenation of oxides of carbon .to methanol and consistingprincipally of a mixture of alcohols of high molecular weight, in theproportion of 50 parts of said product to 50 parts of castor oil.

9. A fluid for use in fluid pressure apparatus comprising rape seed oiland a mixture of higher boiling oxygenated organic liquid productsobtainable as a by-product in the catalytic hydrogenation of oxides ofcarbon to methanol.

10. A fluid for use in fluid pressure apparatus I comprising rape seedoil and a mixture of higher proportions of from 5-95 parts of saidproducts to from-95-5 parts of rape seed oil.

11. A fluid for use in fluid pressure apparatus comprising rape seed oiland a mixture of the higher boiling oxygenated organic liquid productsboiling from 157 C. to 195 C. obtainable as a by-product by thecatalytic hydrogenation of oxides of carbon to methanol and consistingprincipally of a mixture of alcohols of high molecular weight, in theproportion of 31.5 parts of said product to 68.5 parts of rape seed oil.

12. A fluid for use in fluid pressure apparatus comprising liquidpetrolatum and a mixture of higher boiling oxygenated organic liquidproducts obtainable as a by-product in the catalytic hydrogenation ofoxides of carbon to methanol.

13. A fluid for use in fluid pressure apparatus comprising liquidpetrolatum and a mixture of higher boiling oxygenatedo'rganic liquidproducts boiling above 133 C. obtainable as a byproduct by the catalytichydrogenation of oxides of carbon to methanol and consisting principallyof a mixture of alcohols of high molecular weight, in the proportions offrom 5-95 parts of said products to from 95-5 parts of liquidpetrolatum.

14. A fluid for use in fluid pressure apparatus comprising liquidpetrolatum and a mixture of the higher boiling oxygenated organic liquidproducts boiling from C. to 250 C. obtainable as a by-product by thecatalytic hydrogenation of oxides of carbon to methanol and consistingprincipally of a mixture of alcohols of high molecular weight, in theproportion of 25 parts of said

